1. Field of the Invention
The present invention relates to a water base ink for ink-jet recording, an ink cartridge, and an ink jet recording apparatus.
2. Description of the Related Art
In recent years, a high printing speed, which is equivalent to that of the laser printing, is required to be realized in the printing on the plain paper or regular paper in the field of the ink-jet printing. A method, in which the printing dot number is decreased for the plain paper to enhance the permeability of the ink, is exemplified as a method for achieving the realization of the high printing speed. The permeability of the ink can be enhanced by adding a penetrant to the ink. For example, an ink has been suggested, in which diethylene glycol n-hexyl ether (DEGHE) is used as the penetrant (see U.S. Pat. No. 4,985,077 (corresponding to Japanese Patent Application Laid-open No. 1-266173), Japanese Patent Application Laid-open No. 3-14881, Japanese Patent Application Laid-open No. 4-153279, Japanese Patent Application Laid-open No. 8-67840, Japanese Patent Application Laid-open No. 11-166144, Japanese Patent Application Laid-open No. 11-256087, U.S. Pat. No. 5,952,414 (corresponding to Japanese Patent Application Laid-open No. 9-111165), United States Patent Application Publication No. 2007/0263058A1 (corresponding to Japanese Patent Application Laid-open No. 2007-302802), Japanese Patent Application Laid-open No. 2007-302810, Japanese Patent Application Laid-open No. 2008-31260, Japanese Patent Application Laid-open No. 2008-120977, Japanese Patent Application Laid-open No. 11-124524, Japanese Patent Application Laid-open No. 11-116863, and United States Patent Application Publication No. 2006/0176349A1 (corresponding to Japanese Patent Application Laid-open No. 2005-89713)).
However, if a large amount of DEGHE is added to the ink, the vaporization characteristic of the ink is deteriorated to cause the solidification of the ink, the precipitation of a coloring agent, and the aggregation (coagulation or cohesion). Consequently, the nozzle of the ink jet head tends to suffer the clog-up, and the discharge failure or undischarge (unsatisfactory discharge) is caused. Further, if a large amount of DEGHE is added to the ink, it is difficult to remove the ink, for example, from a casing or the like when the ink adheres to a resin material forming the casing or the like of an ink-jet recording apparatus; and a state tends to be given, in which ink dirt (stain) adheres to the casing or the like and the ink dirt remains as it is. If the ink adheres and remains as it is for a long period of time, the deterioration of the resin material forming the casing or the like is caused thereby. Further, DEGHE exhibits a poor water solubility. Therefore, a problem arises such that an amount of DEGHE, which is required to obtain the sufficient permeating power (penetrating power), cannot be added into the ink. Further, DEGHE exhibits a low water repellence. Therefore, an ink using DEGHE tends to adhere to a wall surface of the ink cartridge. Such an ink causes such a problem that the residual amount of the ink cannot be confirmed from the outside and such a problem that the ink is wasted.